/Engine/Source/Runtime/AudioMixer/Public/Quartz/QuartzSubsystem.h
Allow an external clock (not ticked by the Audio Mixer or QuartzSubsystem) to be accessible via this subsystem
void AddProxyForExternalClock ( const [Audio::FQuartzClockProxy](API\Runtime\AudioMixer\Quartz\FQuartzClockProxy) & InProxy )